Isolation of tetracenomycin C-nonproducing Streptomyces glaucescens mutants

We analyzed the properties of tetracenomycin C (TcmC)-nonproducing mutants of Streptomyces glaucescens to establish the nature of pathway intermediates and to provide some information about the genetics of antitumor anthracycline antibiotic production. Using cosynthesis properties and metabolite accumulation data, we classified a collection of 34 TcmC-nonproducing strains into seven different groups. From this information, we deduced the positions of the tcm mutations in relation to a hypothetical TcmC biosynthetic pathway and suggest which pathway enzymes are affected by the different mutations.     

Correlation between Lsp1 (Rs3817198) and Casc (Rs4784227) Polymorphisms and the Susceptibility to Breast Cancer

Background:Breast cancer is classified as one of the common cancers among women worldwide. Within numerous genetic factors involved in the development of breast cancer, lsp1 and casc genes are both located on breast cancer susceptibility locus. While the SNP rs3817198 in lsp1 gene has a twilight association with breast cancer in different populations, casc rs4784227 polymorphisms have been reported to associate with breast tumor appearance in Asian, European, and African ancestry populations. The present report was designed a case-control group aimed at assessing the association of these two SNPs with breast cancer risk in the Iranian population.Methods:In the case-control study of rs3817198 and rs4784227 polymorphisms in 100 women with breast cancer and 100 healthy women were examined by Tetra Arms PCR. Data collected using SPSS software and chi-square test and correlation coefficient were used for statistical analysis.Results:The results of current study showed that the Chi-square of lsp1 rs3817198 and casc rs4784227 polymorphism genotypes in breast cancer, were reported to be 51.613 and 47.920, respectively. Also there has been a significance level of both polymorphisms resulting in the frequency of genotypes in these two polymorphisms between case and control group.Conclusion:Our finding thus suggested that in both polymorphisms, homozygote genotype showed strong correlation with cancer susceptibility. While, TT genotype in lsp1 rs3817198 showed significant association with pathogenic properties, in the case of casc rs4784227 genotypes CC, and in second place, TT showed similar correlation.Key Words: Breast cancer, Casc, Lsp1, Polymorphism     

Effects of Gamma Irradiation and Silver Nano Particles on Microbiological Characteristics of Saffron,Using Hurdle Technology

Saffron, a plant from the Iridaceae family, is the world’s most expensive spice. Gamma irradiation and silver nano particles whose uses are gradually increasing worldwide, have positive effects on preventing decay by sterilizing the microorganisms and by improving the safety without compromising the nutritional properties and sensory quality of the foods. In the present study combination effects of gamma irradiation and silver nano particles packaging on the microbial contamination of saffron were considered during storage. A combination of hurdles can ensure stability and microbial safety of foods. For this purpose, saffron samples were packaged by Poly Ethylene films that posses up to 300 ppm nano silver particles as antimicrobial agents and then irradiated in cobalt-60 irradiator (gamma cell Model: PX30, dose rate 0.55 Gry/Sec) to 0, 1, 2,3 and 4 kGy at room temperature. The antimicrobial activities against Total Aerobic Mesophilic Bacteria, Entrobacteriace, Escherichia Coli and Clostridium Perfringines were higher in the irradiated samples, demonstrating the inhibition zone for their growth. Irradiation of the saffron samples packaged by Poly Ethylene films with nano silver particles showed the best results for decreasing microbial contamination at 2 kGy and for Poly Ethylene films without silver nano particles; it was 4 kGy.     

Ionic relationships in some halophytic Iranian Chenopodiaceae and their rhizospheres

Previous studies on the identification of ion relations in halophytes have revealed that many members of Chenopodiaceae accumulate high amounts of sodium and chloride even in soils with low salinity, indicating a typical pattern which is genetically fixed. In this study, we followed up with the question of ion relations in different halophyte species with different photosynthetic pathways and different salt tolerance strategies over a complete growing season. Soil and plant samples from five species Climacoptera turcomanica (Litv.) Botsch. (leaf succulent-C₄), Salicornia persica Akhani subsp. rudshurensis Akhani (stem succulent-C₃), Halimocnemis pilifera Moq. (leaf succulent-C₄), Petrosimonia glauca (Pall.) Bunge (leaf succulent-C₄) and Atriplex verrucifera M. Bieb. (recreto-halophyte-C₃) were collected over a complete growing season from a salt flat 60 km W of Tehran. The contents of main cations (Na⁺, K⁺, Ca²⁺, and Mg²⁺) and chloride were determined in plant and soil samples. Na⁺ and Cl^? concentration in the shoots of two hygro-halophytes Climacoptera turcomanica and Salicornia persica subsp. rudshurensis were constant over the period of the growing season. In contrast, sodium and chloride in the shoots of Halimocnemis pilifera and Petrosimonia glauca showed respectively an increasing and, in the shoots of Atriplex verrucifera, a decreasing, trend. We did not notice any decreasing trend of K⁺ together with increasing trend of Na⁺ in the shoots of the studied species; however K⁺ in the shoots of all examined species was considerably lower than Na⁺ and Cl^?. It was observed that Climacoptera and Salicornia could absorb and retain calcium even in high salinity conditions, while Halimocnemis and Petrosimonia could not. Na⁺, K⁺, Cl^?, Ca²⁺, and Mg²⁺ contents in the shoots of different types of halophytes (stem-succulent, leaf-succulent and excreting halophyte) or different type of photosynthesis (C₃, C₄) are independent of those in their rhizosphere. We concluded that it is controlled by the genetic characteristic of the specific taxon rather than by the environment.     

Utilization of dibenzothiophene as sulfur source by <Emphasis Type="Italic">Microbacterium</Emphasis> sp. <Emphasis Type="Italic">NISOC-06</Emphasis>

Oil-polluted soils were sampled from National Iranian South Oil Company (NISOC) for isolation and screening of C–S and not C–C targeted Dibenzothiophene (DBT) degrading microorganisms. Microbacterium sp. NISOC-06, a C–S targeted DBT degrading bacterium, was selected and its desulfurization ability was studied in aqueous phase and water-gasoline biphasic systems. The 16srRNA gene was amplified using universal eubacteria-specific primers, PCR product was sequenced and the sequence of nearly 1,500 bp 16srDNA was studied. Based on Gas Chromatography results Microbacterium sp. NISOC-06 utilized 94.8% of 1 mM DBT during the 2 weeks of incubation. UV Spectrophotometry and biomass production measurements showed that the Microbacterium sp. NISOC-06 was not able to utilize DBT as a carbon source. There was no accumulation of phenolic compounds as Gibb’s assay showed. Biomass production in a biphasic system for which DBT-enriched gasoline was used as the sulfur source indicated the capability of Microbacterium sp. NISOC-06 to desulfurize gasoline.     

Immunolocalization of the exocytosis-sensitive phosphoprotein, PP63/parafusin, in Paramecium cells using antibodies against recombinant protein

 We have localized a structure-bound fraction of the exocytosis-sensitive phosphoprotein, PP63/parafusin (PP63/pf), in Paramecium cells by widely different methods. We combined cell fractionation, western blots, as well as light and electron microscopy (pre- and postembedding immunolabeling), applying antibodies against the recombinant protein. PP63/pf is considerably enriched in certain cortical structures, notably the outlines of regular surface fields (kinetids), docking sites of secretory organelles (trichocysts) and the membranes of subplasmalemmal Ca²⁺-stores (alveolar sacs). From our localization studies we tentatively derive several potential functions for PP63/pf, including cell surface structuring, assembly of exocytosis sites, and/or Ca²⁺ homeostasis. Accepted: 4 December 1997